1. Technical Field
This invention relates generally to sleeves for protecting elongate members and more particularly to knit tubular protection sleeves.
2. Related Art
Knit tubular sleeves that provide protection from external elements and that provide a barrier to heat radiation from elongate members, such as exhaust pipes, wires and tubing, contained within the sleeves, are known. The sleeves are commonly knit from abrasion resistant, heat resistant, or fire retardant yarns to withstand relatively high temperatures and to allow portions of the sleeve to expand radially. The sleeves are commonly constructed having a continuous, closed tubular wall, such that the sleeves must be slid in sock-like fashion over the item being protected. Given the closed tubular wall construction, sometimes multiple sleeves are used in combination with one another to accommodate protrusions, e.g., sensors, or members branching from the item being protected, wherein adjacent ends of the sleeves are fastened to one another on opposite sides of the respective obstacle. This complicates the assembly process and adds labor/component cost. Otherwise, to avoid using multiple sleeves, some sleeves have an opening formed in the closed wall to accommodate the respective protrusion and/or member branching from the item being protected, or to facilitate locating the sleeve in a stationary position relative to a protrusion from the item being protected. In order to form the opening, or in some cases multiple openings, the closed wall must be slit, thereby resulting in frayed, loose ends of the yarns forming the closed wall. This generally results in unraveling of the yarns forming the sleeve, thereby reducing its ability to perform as intended and reducing its useful life.
As such, to reduce the risk of degrading the usefulness and life of the closed wall sleeve, it is known to form openings in secondary cutting and sewing operations. In the secondary operations, the cut edges forming the opening are sewn to reduce the likelihood of their unraveling. Unfortunately, these secondary operations add cost to the manufacturing process. In addition, the sewn edges provide a potential origin for future unraveling, should the stitches come loose or broken during use.
In addition, sometimes multiple closed wall portions of a sleeve or sleeves are overlapped with one another to form a multilayered sleeve to minimize the heat radiation outwardly from the item covered by the sleeve. Although this can be effective in reducing heat from radiating outwardly from the sleeve(s), it also retains the heat next to the covered item, thereby impacting its ability to be cooled. As such, it would be desirable to have a sleeve capable of both preventing heat from radiating outwardly in selected areas, while also being able to expel heat from the covered item in other areas to allow the item to be cooled.
Knit sleeves manufactured in accordance with the present invention, among other things, overcome or greatly minimize any limitations of the known sleeves described above.